Preparation of polyaniline nanotubes array based on anodic aluminum oxide template

In this article, the highly ordered polyaniline (PANI) nanotubes array was prepared by in situ polymerization using anodic aluminum oxide (AAO) as template. Polymerization of aniline was confined in the one-dimensional nanochannel of AAO template. The aniline was adsorbed and polymerized preferentially on the pore walls of template. The structure of PANI nanotubes array was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), selected area electron diffraction (SAED) and dynamic force microscope (DFM). The results show that PANI nanotubes are synthesized successfully in the nanopores of template, the diameter and length of PANI nanotubes are closed to the pore diameter and thickness of AAO template, respectively, the arrangement of PANI nanotubes is very regular and uniform, the crystal form of PANI nanotubes is hexagonal, different from pseudo-orthorhombic crystal form of PANI bulk sample, and cell parameters a and b are 0.5008 nm. The change of crystal form is due to the confinement of AAO template, which makes the molecular chain of PANI arrange more ordered.     

Highly ordered uniform single-crystal Bi nanowires: fabrication and characterization

A mechanical pressure injection technique has been used to fabricate uniform bismuth (Bi) nanowires in the pores of an anodic aluminum oxide (AAO) template. The AAO template was prepared from general purity aluminum by a two-step anodization followed by heat treatment to achieve highly ordered nanochannels. The nanowires were then fabricated by an injection technique whereby the molten Bi was injected into the AAO template using a hydraulic pressure method. The Bi nanowires prepared by this method were found to be dense and continuous with uniform diameter throughout the length. Electron diffraction experiments using the transmission electron microscope on cross-sectional and free-standing longitudinal Bi nanowires showed that the majority of the individual nanowires were single crystalline, with preferred orientation of growth along the [011] zone axis of the pseudo-cubic structure. The work presented here provides an inexpensive and effective way of fabricating highly ordered single-crystalline Bi nanowires, with uniform size distributions.     

Controlled synthesis of highly ordered LaFeO3 nanowires using a citrate-based sol–gel route

Highly ordered LaFeO₃ nanowires of complex oxide were controlled synthesized with a porous anodic aluminum oxide (AAO) template by a citrate-based sol–gel route. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the LaFeO₃ nanowires formed a uniform length and diameter, which were determined by the thickness and the pore diameter of the AAO template, respectively. The results of X-ray diffraction (XRD) and the selected area electron diffraction (SAED) indicated that the LaFeO₃ nanowires had a perovskite-type crystal structure. Furthermore, X-ray photoelectron spectroscopy (XPS) demonstrated that stoichiometric LaFeO₃ was formed.     

Aligned nanowire growth using lithography-assisted bonding of a polycarbonate template for neural probe electrodes

This research presents a fabrication method of vertically aligned nanowires on substrates using lithography-assisted template bonding (LATB) towards developing highly efficient electrodes for biomedical applications at low cost. A polycarbonate template containing cylindrical nanopores is attached to a substrate and the nanopores are selectively opened with a modified lithography process. Vertically aligned nanowires are grown by electrochemical deposition through these open pores on polyimide film and silicon substrates. The process of opening the nanopores is optimized to yield uniform growth of nanowires. The morphological, crystalline, and electrochemical properties of the resulting vertically aligned nanowires are discussed using scanning electron microscopy (SEM), x-ray diffraction (XRD), and electrochemical analysis tools. The potential application of this simple and inexpensive fabrication technology is discussed in the development of neural probe electrodes.     

外表面不同孔结构的阳极氧化铝模板的自组织制备

经二次阳极氧化制备了外表面不同孔结构的阳极氧化铝模板.用场发射扫描电镜(FE-SEM)对其形貌进行表征,发现在直接阳极氧化的铝箔的外表面自组装形成了规则的六方形的纳米孔,而在去除铝基、扩孔的另一外表面则形成了规则的圆形的纳米孔,外表面纳米孔的平均直径大约为80nm,孔间距大约为110nm,孔密度约为2.5×10n cm-2.在模板的内部形成相互平行且垂直于AAO模板外表面的纳米管的阵列结构,纳米管的平均直径大约为80nm;AAO模板的厚度大约为10/zm.粉末X射线衍射(XRD)表明模板具有非晶态的结构.记录了阳极氧化过程中的电流一时间曲线,探讨了自组织孔洞的形成机理,提出了新型阳极氧化铝模板制备纳/微米结构材料模拟应用.     

Silver nanowires prepared by modified AAO template method

Thin film containing highly ordered silver nanowires array was prepared by using anodic aluminum oxide (AAO) template method. The morphology of the silver nanowires was confirmed by scanning electron micrograph (SEM). The result of the SEM showed that the silver nanowires were substantive, parallel, and ordered in the AAO template. Diameter distribution of the silver nanowires indicated that the average diameter was about 35 nm. The composition and structure of the Ag nanowires were investigated by Energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) pattern, respectively.     

Electrochemical Fabrication of Pd-Ag Alloy Nanowire Arrays in Anodic Alumina Oxide Template

The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide （AAO） template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy （SEM） and energy dispersed X-ray spectroscopy （EDX） were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X-ray diffraction （XRD） was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V （vs SCE）. The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag＋ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd^2＋ and Ag＋ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.     

Self-organized magnetic nanowire arrays based on alumina and titania templates

Densely packed arrays of magnetic nanowires have been synthesized by electrodeposition filling of nanopores in alumina and titania membranes formed by self-assembling during anodization process. Emphasis is made on the control of the production parameters leading to ordering degree and lattice parameter of the array as well as nanowires diameter and length. Structural, morphological and magnetic properties exhibited by nanowire arrays have been studied for several nanowire compositions, different ordering degree and for different nanowire aspect ratios. The magnetic behaviour of nanowires array is governed by the balance between different energy contributions: shape anisotropy of individual nanowires, the magnetostatic interaction of dipolar origin among nanowires, and magnetocrystalline and magnetoelastic anisotropies induced by the pattern templates. These novel nanocomposites, based on ferromagnetic nanowires embedded in anodic nanoporous templates, are becoming promising candidates for technological applications such as functionalised arrays for magnetic sensing, ultrahigh density magnetic storage media or spin-based electronic devices.     

图案化金属铜纳米线阵列的制备与表征

采用紫外线光刻技术与电化学沉积相结合的方法,成功制备了不同图案的铜纳米线阵列:一种是圆形图案;另一种是QDU图案.首先利用紫外线光刻技术在多孔阳极氧化铝模板(AAO)生成预设图案,以此作为"二次模板";再利用电化学方法将铜纳米线沉积到"二次模板"的开孔中.扫描电镜(SEM)测试结果表明,大面积、高规整的铜纳米线图案阵列各自独立地立在基底上, 同时,用电子能谱(EDS)分析了铜纳米线的化学成分.透射电镜(TEM)也探测到了铜纳米线的微结构.     

Quantificational Etching of AAO Template

Ni nanowires were prepared by electrodeposition in porous anodized aluminum oxide （AAO） template from a composite electrolyte solution. Well-ordered Ni nanowire arrays with controllable length were then made by the partial removal of AAO using a mixture of phosphoric acid and chromic acid （6 wt pct H3PO4：1.8 wt pct H3CrO4）. The images of Ni nanowire arrays were studied by scanning electron microscopy （SEM） to determine the relationship between etching time and the length of Ni nanowire arrays. The results indicate that the length of nanowires exposed from the template can be accurately controlled by controlling etching time.     

Instabilities in nanoporous media

Rayleigh instabilities in thin polymer films confined within nanoporous alumina membranes were studied. Thin films of poly(methyl methacrylate) (PMMA) were prepared by filling cylindrical nanopores in an anodic aluminum oxide (AAO) membrane with a PMMA solution in chloroform followed by solvent evaporation. When the PMMA nanotubes were annealed above the glass transition temperature (Tg), undulations in the film thickness were observed that were induced by a Rayleigh instability. The amplitude of the undulations increased with time and eventually bridged across the cylindrical nanopore in the AAO membrane, resulting in the formation of polymer nanorods with periodic encapsulated holes. A similar behavior was observed when PMMA films were confined within carbon nanotubes (CNTs). The Rayleigh instabilities in these confined geometries offer a novel means of controlling and fabricating the polymer nanostructures. These compartmentalized nanorods may have potential applications as delivery devices.     

Quantiflcational Etching of AAO Template

Ni nanowires were prepared by electrodeposition in porous anodized aluminum oxide (AAO) template from a composite electrolyte solution. Well-ordered Ni nanowire arrays with controllable length were then made by the partial removal of AAO using a mixture of phosphoric acid and chromic acid (6 wt pct H3PO4: 1.8 wt pct H3CrO4). The images of Ni nanowire arrays were studied by scanning electron microscopy (SEM) to determine the relationship between etching time and the length of Ni nanowire arrays. The results indicate that the length of nanowires exposed from the template can be accurately controlled by controlling etching time.     

Template synthesis of highly ordered hydroxyapatite nanowire arrays

Highly ordered hydroxyapatite (HA) nanowire arrays were synthesized using porous anodic aluminum oxide (AAO) template from sol-gel solution containing P₂O₅ and Ca(NO₃)₂. Theresults of transmission electron microscopy (TEM) and scanning electron microscopy(SEM) revealed that the obtained HA nanowires had a uniform length and diameter andformed highly ordered arrays, which were determined by the pore diameter and thethickness of the applied AAO template. The results of X-ray diffraction (XRD) and X-rayphotoelectron spectroscopy (XPS) demonstrated that the major component was HA. Theselected-area electron diffraction (SAED) results indicated that HA was a polycrystallinestructure. This novel method of preparing highly ordered HA nanowires with a large areamight be important for many applications in biomaterials.     

Nanowire array fabricated by Al-Ge phase separation

Phase-separated Al-Ge films, composed of Al nanowire array with diameters ranging from less than 10 to 18 nm embedded in an amorphous Ge matrix, have been prepared by a sputtering method. Similar to lateral phase separation of Al-Si system, sputtered Al and Ge form an Al nanowire array surrounded by a Ge matrix during film growth when the preparation conditions are optimized. Removal of the Al nanowires from the phase-separated Al-Ge films by etching in acid solution provides nanoporous films with a pore density on the order of 10¹⁵ pores/m². Template-assisted growth of Ni nanowires into the nanopores was carried out to increase the potential applications of the phase-separated Al-Ge films.     

多孔阳极氧化铝模板法交流电沉积单晶镍纳米线阵负

一维纳米材料在光学、电学、磁学等领域有着广阔的应用前景。采用二次阳极氧化法,结合逐级降压法制备了多孔阳极氧化铝（AAO）模板,然后在其上交流电沉积了单晶镍纳米线阵列。利用SEM,XRD,TEM等对镍纳米线阵列的形貌和结构进行了表征,探讨了沉积效果与沉积电流密度一时间曲线和稳定沉积电流密度大小之间的关系。结果表明：沉积电...     

Nanopatterned silicon emitters of a solar cell fabricated by anodic aluminum oxide masks

We investigated the nanopattern transferring process by a template of anodic aluminum oxide and the formation of a nanoporous aluminum oxide layer on a Si solar cell by the anodization process of Al thin films. The anodization process provided a template to transfer the nanopattern onto the Si surface. The small-sized nanoporous alumina template was attached to be covered on the textured surface and played the role of etching mask in the F-based dry etching process. Furthermore, we deposited an Al thin film onto the Si surface and the subsequent anodization process was performed. The alumina formulated on the deposited Al thin film did not show the array of nanoporous structure and no nanopatterns were transferred onto the surface. The large-areal alumina deposited on the Si surface showed enhanced photo-absorption in the ultraviolet spectral region of 243 nm, but increased the photo-reflectance in the visible and infrared spectral regions when compared to the Si-bare sample.     

Fabrication and characterization of a flow-through nanoporous gold nanowire/AAO composite membrane

The fabrication of a composite membrane of nanoporous gold nanowires and anodic aluminum oxide (AAO) is demonstrated by the electrodeposition of Au-Ag alloy nanowires into an AAO membrane, followed by selective etching of silver from the alloy nanowires. This composite membrane is advantageous for flow-through type catalytic reactions. The morphology evolution of the nanoporous gold nanowires as a function of the diameter of the Au-Ag nanowire 'precursors' is also investigated.     

Synthesis of single crystal metal sulfide nanowires and nanowire arrays by chemical precipitation in templates

Single crystal metal sulfide nanowires and nanowire arrays were synthesized by chemical precipitation reaction in the channels of anodic aluminum oxide templates under ambient conditions with simple inorganic salts as precursors. Aligned metal sulfide arrays were achieved by dissolving the template. This template-directed synthesis yielded well-defined nanowires of varied lengths and diameters for almost all precursors. The crystal quality of metal sulfide nanowires was concentration-dependent, high single crystal nanowires were achieved at low concentrations.     

用低纯度铝制备AAO模板及其结构研究

在0.3mol/dm3草酸溶液中,通过不同纯度铝的恒电位二次阳极氧化制备了纳米孔氧化铝模板,并用场发射扫描电子显微镜(FE-SEM)和原子力显微镜(AFM)观察模板结构.实验结果表明,一次氧化除膜后低纯度铝基体表面呈现较为规则的六边形结构,这种蜂巢结构有利于二次氧化过程中获得有序度更高的纳米孔模板.低纯度铝制备的模板表面被晶界分隔为微小的区域,只是在较窄区域内才出现六边形规则排列的纳米孔.恒电位40V时所得模板经扩孔处理后,孔径由35nm增大到100nm左右,且孔径大小几乎一致.从纳米孔的有序度来看,由低纯度铝制备模板还需要进一步优化阳极氧化参数.     

简单蚀刻法制备具有可控高度的金属纳米线阵列

采用多孔阳极氧化铝(AAO)作为模板,运用电化学沉积法在模板的微孔中组装金属Ni纳米线,然后用磷铬酸蚀刻表层AAO模板,暴露出规整有序、具有可控长度的Ni纳米线阵列.分别用SEM、TEM与SAED对Ni纳米线阵列进行了表征.研究了蚀刻时间与AAO模板质量的减少及暴露出来的Ni纳米线阵列长度之间的关系.结果表明,磷铬酸是较NaOH溶液更为温和有效的AAO模板蚀刻剂,通过控制模板溶解时间,可以实现对裸露于AAO模板外纳米线长度的精细有效控制.该蚀刻方法普遍适用于以AAO为模板所制得的准一维纳米阵列结构.